External Merge Tool Not Launching

[Steve Macleod]

I am attempting to use Meld as an external merge tool with the following config:

Merge Tool: Custom

Diff Command: C:\Program Files (x86)\Meld\Meld.exe

Arguments: $LOCAL $BASE $REMOTE --auto-merge --output=$MERGED

When I right-click on a conflicted file and select 'Resolve Conflicts' > 'Open External Merge Tool' I get the dialog for 'Visual Merge in Process' but the merge tool does not open.

The path is correct.

I am using Sourcetree for Windows, v2.6.10.0. System Git v2.17.1.

Does anyone have any ideas why it is not opening Meld?

[minnsey · Accepted solution]

We don't formally test with Meld but trying it out now for diff and merge it seems to be working for me.

Its worth checking what 

>git config

returns, I get 

mergetool.sourcetree.trustexitcode=true
mergetool.sourcetree.cmd='C:/Program Files (x86)/Meld/meld/meld.exe' $LOCAL $BASE $REMOTE --auto-merge --output=$MERGED
difftool.sourcetree.cmd='C:/Program Files (x86)/Meld/meld/meld.exe' $LOCAL $REMOTE

Also check you are not trying it on a file that is deleted as part of the merge, that is a known issue for all external merges

Also check the file names do not have spaces in them, you can work around this by using arguments like

\"$LOCAL\" \"$BASE\" \"$REMOTE\" --auto-merge --output=\"$MERGED\"

[Steve Macleod]

In this case it would seem that GIT is seeing the remote file as being deleted, however I am not sure why this is. Happy to accept this answer as it is the cause of the merge tool not opening.

[minnsey]

Yes, diffing is a little problematic when a file is deleted on one side of the merge. 

[Paweł Długosz]

I am so dissapointed with sourcetree. Every version have so many bugs. When you find how to fix one the new one is problem. Now I also can't lunch DiffMerge software even i used it before!!!

[vmelnic]

Agree with you Pawel. Yearly several years ago when sourcetree was written using Qt it was much more stable from my point of view.

[samlachance]

In case anybody else is having problems getting their external diff tools to open (I'm using Meld with Mercurial), there appears as if there my be a problem parsing the command variables atm.
https://jira.atlassian.com/browse/SRCTREEWIN-11088

If "external diff" isn't working for you, you can try removing the arguments entirely
($LOCAL, $REMOTE, etc), and see if it will at least open. The files might not be ordered the way you like them to be, but if it launches the external diffs in the meantime, it's better than nothing... Hopefully it'll get patched soon.